Earth Notes

11:10 pm

Tue February 17, 2009

Earth Notes - Artificial Lights and Wildlife

If you've ever suffered jet lag, you have an idea how animals can become disoriented when their biological clocks are disrupted by too much light at night.

In a world where true darkness has become rare, biologists are increasingly concerned about the effects of artificial lighting on wildlife. They are finding that hundreds of species of birds, mammals, amphibians, reptiles, fish, and insects alter their behavior in the glare of overlit towns and roads.

Nocturnal animals are the most vulnerable. Snakes, for example, will avoid coming out at night to look for food, and they become easier prey.

Moths are drawn to lights, but if they spend too much energy there they have trouble with navigation and reproduction.

Birds are attracted to, or trapped by, beacons and lights on towers and tall buildings. They can end up colliding with walls, circling light sources until exhausted, or being thrown off course during migration.

Mammals are also affected, according to conservation biologist Paul Beier of Northern Arizona University. Rabbits and rodents tend not to forage at night in bright light. Bears, deer, mountain lions, and other large mammals that disperse at night will avoid crossing lighted roadways and will be blinded for a time by lights.

The Colorado Plateau remains one of the darkest spots on the nation's map. Still, it's worth lessening light pollution by fully shielding all outdoor lights; using red or yellow, rather than blue, lights; and turning lights on only when, and where, they're needed.